package Code_block_package;

public class Code_block_demo1 {
    public static void main(String[] args) {
        {
            int a = 0;
        }
        //因为当代码执行到这里时，变量a就从内存中消失了
        //error:  System.out.println(a);

        //创建对象
        Student s = new Student();

        Student s1 = new Student("张三", 23);
    }
}
